手动打开的 Excel / Notepad 文件（由用户打开），如何通过 java 程序识别此文件

@H_801_10@以下方法基于 Windows...

首先，在记事本、Excel等软件中打开文件时，是用带参数的命令行执行的，即如果记事本在E:\test.txt中打开，启动的命令行参数为

notepad E:\test.txt

在 Windows 中，我们可以使用 wmic 命令来获取应用程序的启动参数。具体用法是：

wmic process where caption="{exe_namE}" get caption,commandline /value

例如查询记事本中打开的命令行参数的cmd命令是：

wmic process where caption="notepad.exe" get caption,commandline /value

返回结果类似如下：

Caption=notepad.exe
CommandLine="C:\Windows\system32\NOTEPAD.EXE" H:\2019Summer\软件工程\任务.txt

上面的“H:\2019Summer\软件工程\任务.txt”是我目前用记事本打开的文件。 我们需要做的是解析结果String，这里是我的示例java代码：

import java.io.bufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.text.messageFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

public class GetOpenedFile {
    //QUERY_COMMAND
    private static String QUERY_COMMAND = "wmic process where caption=\"{0}\" get caption,commandline /value";
    private static String NOTEPAD_NAME = "notepad.exe";
    private static String EXCEL_NAME = "excel.exe";

    /**
     * get execName command line
     *
     * @param execName like notepad.exe,excel.exe
     * @return the all command line of the process {execNamE}
     */
    private static List<String> getExecCommandLines(String execName) {
        Runtime runtime = Runtime.getRuntime();
        List<String> commandLines = new ArrayList<>();
        try {
            Process process = runtime.exec(messageFormat.format(QUERY_COMMAND,execName));
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(process.geTinputStream(),"GB2312"));//set your cmd charset(default value is utf8)
            String caption = null;
            while (true) {
                String s = bufferedReader.readLine();
                if (s == null) {
                    break;
                }
                if (s.length() == 0) {//skip blank String
                    conTinue;
                }
                //get the file name
                if (s.startsWith("Caption")) {
                    caption = s.subString("Caption=".length());
                    conTinue;
                }
                if (s.startsWith("CommandLine=") && caption != null) {
                    int index = Math.max(s.indexOf(caption),s.indexOf(caption.toUpperCase()));//maybe the exe file name is ALL UPPER CASE,eg. NOTEPAD.EXE
                    index += caption.length()
                            + 1;//Double quotes "
                    String commandLine = s.subString(indeX);// command Line
                    commandLine = commandLine.StripLeading();//Strip leading white space
                    commandLines.add(commandLinE);
                }
            }
        } catch (IOException E) {
            e.printStackTrace();
        }
        return commandLines;
    }

    /**
     * get notepad opened files
     *
     * @return notepad opened files
     */
    public static List<String> getNotepadopenedFiles() {
        List<String> commandLines = getExecCommandLines(NOTEPAD_Name);
        return commandLines.stream()
                .filter(s -> s.length() > 0)//skip empty command line
                .collect(Collectors.toList());
    }

    /**
     * get excel opened files
     * @return excel opened files
     */
    public static List<String> getExcelOpenedFiles() {
        List<String> commandLines = getExecCommandLines(EXCEL_Name);
        return commandLines.stream()
                .filter(s -> s.length() > 0)//skip empty command line
                .map(s -> {             //map result of "filename" to filename
                    if (s.startsWith("\"") && s.endsWith("\"")) {
                        return s.subString(1,s.length() - 1);
                    } else {
                        return s;
                    }
                })
                .collect(Collectors.toList());
    }

    public static void main(String[] args) {
        //console printed
//        [H:\2019Summer\软件工程\任务.txt]
//        [E:\info.xLSX]
        System.out.println(getNotepadopenedFiles());
        System.out.println(getExcelOpenedFiles());
    }
}